Overexpression of CD7 in classical Hodgkin lymphoma-infiltrating T lymphocytes.
BACKGROUND
Diagnosis of Hodgkin lymphoma (HL) is sometimes complicated by the scarcity of neoplastic cells in a reactive inflammatory background. Immunophenotyping by flow cytometry (FC) has not played a significant role in HL diagnosis because of its consistent failure to identify these neoplastic cells. However, HL-infiltrating T cells have been shown to play a role in HL pathogenesis. This study characterizes the FC immunophenotype of these T lymphocytes to determine whether they can be used to assist in the diagnosis of HL.


METHODS
Cell suspensions from 76 lymph nodes involved by HL and 156 lymph nodes with reactive lymphadenopathy (LAD) were analyzed by flow cytometry to assess the expression of T-cell antigens.


RESULTS
The CD4:CD8 ratio and CD7 expression in both CD4(+) and CD8(+) T cells are increased in HL compared with reactive lymph nodes and there are significant differences between these features in different subtypes of HL. However, only the expression of CD7 in CD4(+) T cells distinguishes between HL and reactive LAD. This is especially true for classical HL in younger patients. Using a CD7 mean fluorescence intensity (MFI) cutoff value generated by this data, 37/47 FNA specimens were correctly diagnosed.


CONCLUSIONS
There are significant differences in the immunophenotypes of HL-infiltrating T cells. Of these, the CD7 expression in CD4(+) T cells discriminates between HL and reactive LAD, suggesting that this could be a useful and practical adjunctive tool in the diagnosis of HL. It may also further our understanding of the pathophysiology of this disease.
Seegmiller
Adam C
AC
Department of Pathology, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Blvd., Dallas, TX 75390-9072, USA. adam.seegmiller@utsouthwestern.edu
Karandikar
Nitin J
NJ
Kroft
Steven H
SH
McKenna
Robert W
RW
Xu
Yin
Y
D000328:Adult; D019011:Antigens, CD7 / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D017252:CD3 Complex / Q000096:biosynthesis; D015704:CD4 Antigens / Q000096:biosynthesis; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism*; D016827:CD8 Antigens / Q000096:biosynthesis; D018414:CD8-Positive T-Lymphocytes / Q000378:metabolism*; D005260:Female; D005434:Flow Cytometry; D006689:Hodgkin Disease / Q000175:diagnosis / Q000378:metabolism*; D006801:Humans; D016130:Immunophenotyping; D016246:Lymphocytes, Tumor-Infiltrating / Q000378:metabolism*; D008297:Male; D012680:Sensitivity and Specificity; D016176:T-Lymphocyte Subsets / Q000378:metabolism*
D019011:Antigens, CD7; D017252:CD3 Complex; D015704:CD4 Antigens; D016827:CD8 Antigens